• Journal of Ecology and Environment
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• v.38 no.1
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• pp.1-14
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• 2015

Whilst it is clear that increasing temperatures from global environmental change will impact the positions of alpine treelines, it is likely that a range of regional and local scaled factors will mediate the overall impact of global scale climate drivers. We summarized 12 categories of abiotic and biotic factors as 4 groups determining treeline positions. First, there are global factors related to climate-induced growth limitation and carbon limitation. Second, there are seven regional and local factors related to treeline dynamics including frost stress, topography, water stress, snow, wind, fire and non-fire disturbance. Third, species-specific factors can control treeline dynamics through their influence on reproduction and life history traits. Fourth, there are positive feedbacks in structuring the dynamics of treelines. Globally, the commonly accepted growth limitation hypothesis is that growth at a treeline is limited by temperature. Meanwhile, positive feedbacks between canopy cover and tree establishment are likely to control the spatial pattern and temporal dynamics of many treelines. The presence of non-linear dynamics at treelines has implications for the use of treelines as barometers of climate change because the lagged responses and abrupt shifts inherent in non-equilibrium systems may combine to mask the overall climate trend.

• Journal of Korea Game Society
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• v.15 no.3
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• pp.79-86
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• 2015

Effective feedback plays a key role in education environments to motivate the students and to maintain their flow. However, there usually lacks in providing effective feedbacks in education environments due to an excessive number of students and insufficient class times. The purpose of this paper is to analyze the educatees' response on game like feedback using App. In this paper, Class123 App developed and published by BravePops was used. During one semester, Class123 App had been used in engineering class and the educatees' responses on game like feedbacks using Class123 App are analyzed. Statistical analysis results show that the feedbacks using Class123 App made positive effects to motivate the students. Especially, the positive feedbacks were more effective than the negative feedbacks.

• The Korean Journal of Ecology
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• v.16 no.1
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• pp.115-131
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• 1993

Six nutrient cycles involving terrestrial plants are identified and characterized. Plants affect biotic and abiotic cycles through their effects on soil properties. They determine their internal nutritional status and nutrient concentrations in their environment via internal and external cycles. Contributions of organic matter to mycorrhizal, trophic, and detrital mediated external cycles and alterations of nutrient concentrations by plants can promote positive feedbacks leading to increased availability and retention of soil nutrients in open systems. Recognizing alternative cycles through plants leads to a definition of nutrient use efficiency for ecosystems: the ratio of system production to nutrient content of organic matter. A simple graph model to predict changes of nutrient use efficiency during primary succession is then presented.

• Journal of the Korean Society of Costume
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• v.55 no.4 s.94
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• pp.79-94
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• 2005

The goal of this research, contorted from the perspective of media aesthetics, is to uncover the ways how mechanical/cybersensual fashion products express aesthetic characteristics of cybernetics, by comparing them with digital products designed by an application of cybernetics. The other goal is to provide a cultural and design framework of cybernetics as d digital-environmental medium for fashion in which hightech and human sensibilities are fused. The results urged to explore two new contrasting perceptual possibilities for an understanding of digital technology application: negative and positive feedbacks. Cybernetic optimism, centered on technological dimensions, focuses on a concept of fashion that emphasize instrumental aspects-efficiency and convenience. In contrast, cybernetic pessimism focuses on digital fashion that expresses environmental destruction and the loss of human identity. A comparative analysis of the aesthetics of expression in digital fashion design and digital industrial products from a cybernetic perspective showed that in digital environment society, the combination of negative and positive feedbacks resulted in design products in which internal and external aspects of beauty complemented each other.

• Journal of Digital Convergence
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• v.16 no.5
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• pp.469-476
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• 2018

The purpose of this study was to examine the relations and analyze the mediation effect that exists between the feedback types by professors of university physical education and self-efficacy and sports continuance. The sampling method was used to survey physical education university students from three different universities located in the Greater Seoul Metropolitan Area. 309 samples were ultimately selected as valid samples. Data processing was carried out by using SPSS 18.0 and AMOS 18.0. The fidelity of the whole model was assessed through this process and then the theory was tested. The results were as follows. Firstly, if the perceived feedbacks by the professor were complimentary/encouragement and performance knowledge/positive nonverbal feedbacks it had a positive effect. Negative nonverbal perceived feedback had a negative effect forecast. Secondly, complimentary/encouragement perceived feedbacks by the professor did not have a meaningful impact on sports continuance index. Performance knowledge/positive nonverbal feedback resulted in static effect while negative nonverbal feedback had a negative effect. Lastly, self-efficacy served a meaningful mediation role in the relation between negative nonverbal feedback by the professor and sports continuance.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.6
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• pp.754-759
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• 2007

The information recommendation system offers selected documents according to information needs of dynamic users. User's needs are expressed as profiles consisting of one or more words and may be changed into some specifics through relevance feedback made by users during the recommendation process. In previous research, users have entered relevance information by taking part in explicit relevance feedbacks and learned user profiles using the positive relevance feedbacks. In this paper, we learn user profiles using not only positive relevance feedback but negative relevance feedback and reinforcement learning. To compare the proposed with previous method, we performed experiments to evaluate recommendation performance of the same topic. As a result, the former shows the improved performance than the latter does.

• Journal of KIISE:Databases
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• v.34 no.3
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• pp.193-205
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• 2007

Increasing amount of digital images requires more accurate and faster way of image retrieval. So far, image retrieval method includes content-based retrieval and keyword based retrieval, the former utilizing visual features such as color and brightness and the latter utilizing keywords which describe the image. However, the effectiveness of these methods as to providing the exact images the user wanted has been under question. Hence, many researchers have been working on relevance feedback, a process in which responses from the user are given as a feedback during the retrieval session in order to define user’s need and provide improved result. Yet, the methods which have employed relevance feedback also have drawbacks since several feedbacks are necessary to have appropriate result and the feedback information can not be reused. In this paper, a novel retrieval model has been proposed which annotates an image with a keyword and modifies the confidence level of the keyword in response to the user’s feedback. In the proposed model, not only the images which have received positive feedback but also the other images with the visual features similar to the features used to distinguish the positive image are subjected to confidence modification. This enables modifying large amount of images with only a few feedbacks ultimately leading to faster and more accurate retrieval result. An experiment has been performed to verify the effectiveness of the proposed model and the result has demonstrated rapid increase in recall and precision while receiving the same number of feedbacks.

• English Language & Literature Teaching
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• v.9 no.2
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• pp.151-171
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• 2003

This paper critically reviewed the role of negative feedback in second language acquisition with a focus on recasts based on the findings of recent research investigating the effects of recasts on second language acquisition. First, recasts as negative feedbacks or negative evidence were reviewed in terms of Pinker's four criteria: the evidence of existence, availability, use, and necessity of recasts in second language acquisition. Second, the issue of the nature of recasts, whether they have benefits in SLA as a negative or positive evidence, was discussed with reference to Leeman(2003)'s research findings. Then, in relation to availability and use of recasts, the issue of the extent that they are noticed by learners was reviewed based on the findings from Philp(2003)'s study. Finally, the limitations of these two studies and the research orientation of future study were mentioned.

• ETRI Journal
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• v.27 no.1
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• pp.1-12
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• 2005

We propose a heuristic buffer management scheme that uses both positive and negative acknowledgments to provide scalability and reliability. Under our scheme, most receiver nodes only send negative acknowledgments to their repair nodes to request packet retransmissions while some representative nodes also send positive acknowledgments to indicate which packets can be discarded from the repair node's buffer. Our scheme provides scalability because it significantly reduces the number of feedbacks sent by the receiver nodes. In addition, it provides fast recovery of transmission errors since the packets requested from the receiver nodes are almost always available in their buffers. Our scheme also reduces the number of additional retransmissions from the original sender node or upstream repair nodes. These features satisfy the original goal of treebased protocols since most packet retransmissions are performed within a local group.

• 한국경영정보학회:학술대회논문집
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• 2007.06a
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• pp.395-400
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• 2007

Previous studies present the mixed results on online reputation mechanism. In this study, we have found that an approach based on Bayesian statistics can explain most results of previous studies which are conflicting with each others. With this model, we explain why negative ratings have more significant marginal impacts on sellers' reputation than positive ones do. Furthermore, we even show why the feedbacks with a few negative ratings may increase the value of the item and final prices by confirming buyers' prior beliefs on the sellers' reputation much more than those without negative ratings. Also, we explain why there are not many negative ratings. Even though some studies suggest this because of generosity of users, our model shows that the reason is that the existence of FS itself prevents bad sellers from participating to the market as a signal itself. Even further, we show how this extreme tendency of positive ratings gets even stronger as markets evolve. Finally, to validate our analytical results, we examine the previous studies and see what factors effect the outcomes of their analyses.